Franz Jacob Wagner was born in August 2001 in Berlin, Germany. He is the son of Beate Wagner and Axel Schulz. Wagner joined Germany's Alba Berlin side in 2018 and won the BBL Best Young Player Award. He committed to play for the University of Michigan, where his older brother, Moritz, played. The forward averaged 11.6 points, 5.6 rebounds and 1.3 steals across 27 games during his 2019-20 NCAA season. He was named to the 2020 Big Ten All-Freshman team. Wagner improved during his sophomore campaign by averaging 12.5 points, 6.6 rebounds and 3.0 assists across 28 games during the 2020-21 NCAA season. He was an integral member of a Wolverines team that advanced into the NCAA Tournament's Elite Eight. Wagner was named to the 2021 All-Big 10 second team by coaches and All-Big 10 third team by media members. He declared for the 2021 NBA Draft after two seasons at Michigan. Wagner was selected eighth overall by the Orlando Magic.